1. Field of the Invention
The present invention relates to a process and a device for regulating the power applied to a load from a rectified alternating voltage source by suppressing p half cycles every n half cycles.
2. Description of the Prior Art
A known process for varying the average power applied to a load from an alternating network consists in interrupting the load circuit periodically. This process has been implemented in the prior art by progressively charging a capacitor connected between the gate and the cathode of a thyristor by way of a variable resistor with a rectified alternating voltage. The voltage at the terminals of the capacitor thus increases with each half cycle of the supply voltage. When it reaches a predetermined threshold value the charge on the capacitor is transferred to the control terminal of the thyristor which immediately closes the load circuit or which causes a main interrupter to open. In the case of this type of prior art device, to obtain passage of a full half cycle and reduce disturbances produced by the rapid closing of the interrupter, the latter must comprise a zero voltage control device which inhibits its conductivity at all times other than when the mains voltage (or rather the voltage at its terminals) has a very low absolute value. Inhibiting circuits or circuits triggering at zero are generally relatively complicated.